Do you have evidence for this? I seem to recall that low-mpg light trucks and SUVs were wildly popular in the US until the price of gasoline went to $4.
Is that due to CAFE or due to consumer preference for fuel-efficient cars within a class? Since MPGS are heavily touted in advertising, it seems to be related to consumer preference
I'd credit most of that improvement on electronic engine control, and that really kind of had to evolve somewhat after 1980. You could see good improvement in cars from that time frame just by replacing the coil system with an SCR based ignition.
It's also difficult to explain how brittle a 1980 car's fuel handling system was. Now, having both controlled by the same computer leads to much improvement.
Alternative narrative: Customer demand shifted to cars with higher mileage. Auto makers stopped resisting higher CAFE standards because the minor increment was meaningless. See also: The ongoing debate over minimum wage laws and unemployment.
Inferring causation from correlation is not "pretty simple", but a lot of poor decisions are made under that assumption.
I can tell you for a fact that at least on large diesel truck forums when gas/diesel hit $4/gallon the number of used trucks being posted for sale was staggering. The number of people who couldn't afford to fill their trucks up and still make a payment was almost comical.
